Cisco IOS is proprietary software. You must have a valid service contract (SmartNet) to legally download s6t64-adventerprisek9-mz.spa.155-1.sy10.bin from CCO (Cisco Connection Online).
The s6t64 designation confirms this image is built for the , most notably the Cisco 1941 . s6t64-adventerprisek9-mz.spa.155-1.sy10.bin
: IOS Version 15.5(1)SY10, a maintenance release for the SY train. Are you performing this upgrade on a VSS (Virtual Switching System) setup or a standalone chassis? Cisco IOS is proprietary software
s6t64-adventerprisek9-mz.spa.155-1.sy10.bin is a Cisco IOS software image specifically for the Catalyst 6807-XL 6500-E series switches equipped with Supervisor Engine 6T (Sup6T) Cisco Community Proper Boot Post / Configuration : IOS Version 15
This is a firmware image for a Catalyst 6500 series switch with a Supervisor Engine 6T , containing full enterprise routing and strong encryption.
: Advanced Enterprise Services feature set with strong encryption (K9). 155-1.SY10